Abstract: There is great potential of marine petroleum in the Nanpanjiang Depression. So far, no achievement has been reached due to lack of understanding of reservoir characters. This paper deals with the carbonate reservoir properties, including lithology and storage space of the carbonates, based on surface and subsurface data. The controlling factors of the reservoir, such as depositional process and diagenesis were studied. It is concluded that the best reservoirs are the limestone and dolomite of and reef flat facies of Middle Devonian, Upper-Mid Carboniferous and Permian. According to the reservoir properties, they are evaluated as the typeⅡ-Ⅲ of reservoirs. The most favorable reservoir, i.e. the reef flat deposits deposited along the margins of the carbonate platform margin is widely distributed in the northwest part of the study area.